Rolling mill

ABSTRACT

This disclosure of this invention relates to a roll stand of a rolling mill wherein the working rolls are lowered and raised together with their corresponding chocks, in which on the bottom side of the upper roll or on the upper side of the bottom roll there are mounted spacer pins which in the rolling operation pass into corresponding indentations on the opposite surfaces of the chocks of the other roll, but which during roll changing when the roll sets are lowered or raised engage supporting surfaces of the opposite surfaces of the chocks of the other rolls, subsequent to a relative displacement of both rolls in axial direction, to thereby maintain the rolls at a distance to each other during roll changing.

ilnited States Patent 1 Marten [54] ROLLING MILL [75] Inventor: Hans Friedrich Marten, Kreuztal- Kredenbach, Germany 3/1950 Norlindh ..72/238 7/1953 Friedman ..72/238 Primary Examiner-Milton S. Mehr Attorney-Henry C. Westin [57] ABSTRACT This disclosure of this invention relates to a roll stand of a rolling mill wherein the working rolls are lowered and raised together with their corresponding chocks, in which on the bottom side of the upper roll or on the upper side of the bottom roll there are mounted spacer pins which in the rolling operation pass into corresponding indentations on the opposite surfaces of the chocks of the other roll, but which during roll changing when the roll sets are lowered or raised engage supporting surfaces of the opposite surfaces of the checks of the other rolls, subsequent to a relative displacement of both rolls in axial direction, to thereby maintain the rolls at a distance to each other during roll changing.

1 Claim, 3 Drawing Figures PATENTEDJUN 5197s 3.736, 785

SHEET 1 [1F 2 Fig.1

s I 19\. T

INVENTOR HANS-FRIEDRICH MARTEN HENRY C. WESTIN ATTORNEY PATENTEUJUH 5l975 3,736,785

SHEET 2 OF 2 LNVENTOR ATTORNEY HENRY C. WESTiN HANS-FRIEDRICH MAR?EN Hm THU r ROLLING MILL Such an arrangement is generally known, in part, through the disclosure of U. S. Pat. No. 3,541,830 that issued to H. Bohnenkamp et al. on Nov. 24, 1970. In this patent the chocks of the bottom roll on their upper side and the chocks of the upper roll on their bottom side have cooperating steps arranged in an axial direction. During rolling they allow the rolls to be raised and lowered without interference; whereas, during roll changing, after lateral displacement relative to each other, the step of the upper roll chocks engages the step of the chocks of the bottom rolls in a supporting relationship. By this, the task is solved to obtain a stable distance between the upper and bottom rolls while changing rolls.

But the steps worked into the interworking surfaces of the chocks of the upper and bottom rolls, on one hand, represent a large expense because they can only be manufactured with exactitude by complicated milling operations. On the other hand, the steps formed on the chocks allow for only a limited height displacement between the rolls at a fixed distance from each other for the changing of the rolls because through the making of relatively high step heights an excessive weakening of the chocks would occur. In the case of relatively low step heights, subject to the attainable low height displacement, differently designed chocks are necessary for the rolls of different diameters, thus resulting in high construction expenditures for the roll stands.

The object of the invention is to further develop the known roll stand according to the aforesaid U. S. Pat. No. 3,541,830. More particularly, the object is to improve the construction of the spacer devices which assure the maintaining of the distance between the bottom rolls and the upper rolls of a set of rolls when changing the rolls, which on one hand can be produced easily and inexpensively and which would also allow a height displacement by means of which a larger roll diameter difference can be bridged. Furthermore, a more precise fixation of the rolls of a set of rolls to each other and an assured synchronization thereof during the changing process.

The solution, in accordance with the invention, consists of providing spacer devices in the form of at least two pins to which on the opposite surfaces of the chocks of the roll there are assigned recesses in the form of bores into which the pins extend, preferably without touching in a manner not to restrict vertical movement of the rolls during rolling.

A remarkable characteristic of the invention is that the free ends of the pins provided on the chocks present conic ends to which there are assigned suitable centering depressions in an axial direction of the rolls on the surfaces of the other chocks lying next to the bores and on the same side of the pins. In accordance with the invention the centering depressions are arranged in an axial direction displaced to a certain extent in relation to the bores in such a manner that the pins provide during roll changing a stable stop connection between the rolls of a roll set in addition to holding them apart.

In order to assure the highest possible height displacement between the rolls of a roll set and thereby to allow the utilization of the same set of chocks for roll sets of large diameter differences, the invention provides for the pins, bores and centering depressions to be located as closely as possible to the lateral bearing surfaces of the chocks, i.e., the surfaces furthest away from the bores of the bearings of the rolls.

The following drawings represent the preferred form of the present invention, in which:

FIG. 1 is a schematic simplified representation of a portion of a roll stand with the rolls illustrated in their operating positions, except that the lower roll is shown supported on roll changing rails,

FIG. 2 is a view similar to FIG. 1, however, with the rolls in a position for carrying out the roll changing operation, and

FIG. 3 is an end elevational view of the parts shown in FIG. 2, but including in addition the entire mill stand.

According to usual mill design, the drawings show that in the windows 1 of both roll housing 2 the upper work roll 3 is displaceably supported for elevational height setting on vertical movement of their chocks 5 by an upper mill screw, as is the bottom work roll 4 through its chocks 6 by a lower mill screw. The chocks 5 and 6 of the rolls 3 and 4 are urged apart by roll balance piston cylinder assemblies which, as shown, engage horizontal projections formed on the chocks. The drawing also shows the chocks 6 of the bottom roll 4 supported on a pair of rails which, as noted before, depict the roll changing condition. To place the roll in the position shown in FIGS. 2 and 3 the roll balance associated with the chocks 5 is also utilized to lift the upper roll 3 with its chocks from the bottom roll 4 and lower it again after the roll 4 has been moved axially which operation will be explained more fully later on.

The various other components of the mill stand, such as, the backup roll assemblies, some of which are shown better in the aforesaid U. S. Pat. No. 3,54l,830, need not be described since they are well known in the art.

So that both work rolls 3 and 4 of the roll set are kept at a predetermined distance by maintaining a mutual stable supporting position when they are removed from the roll housings 2 by means of the roll changing device 13, special provisions are provided. According to FIGS. 1 to 3 of the drawings, each chock 6 of the bottom roll 4 is provided on the surface facing the roll gap with two pins 18 which are located near both lateral bearing surfaces of the chocks 6 adjoining the gliding surfaces of the housing windows 1. Each chock 5 of the upper roll 3 is, according to FIGS. 1 to 3 of the drawings, correspondingly provided on the surface facing the roll gap with two bores 19 into which the pins 18 pass, preferably without touching, during the rolling operation as it can clearly be seen from FIG. 1 of the drawings.

In preparation for roll changing the upper roll 3 is lifted with its chocks 5, for instance, by means of the roll balance piston cylinder assemblies until the pins 18 of the chocks 6 protrude completely from the bores 19 of the chocks 5. Subsequently, the bottom work roll 4 with its chocks 6 is transported by means of the roll changing device 13 in an axial direction relative to the rolls a predetermined distance indicated by the legend X in FIG. 2. In this movement the lower work roll is separated from the lower backup roll which has been lowered by the mill screw. Thus, the pins 18 are displaced away from the bores 19 and arrive directly below a surface zone 20 of the upper roll chocks 5 adjoining the bores 19. Through an adequate movement of the roll balance piston cylinder assembly, the upper work roll 3 with its chocks 5 is lowered until the chocks with their surface zone 20 are supported on the free end of the pins 18. The roll bodies of the upper work roll 3 and bottom work roll 4 are thereby kept at a distance from each other, that is to say, they cannot touch during the execution of the roll changing process.

in order for both rolls 3 and 4 of the roll set to be maintained in their contact-free supporting position stably relative to each other during roll changing, the free ends of the pins 18 are provided with conic end 21, while into the surface zone 20 of the chocks 5 there are provided complementing centering depressions 22. As shown in FIG. 2 in the displacement position X of the rolls 3 and 4 as well as that of the chocks 5 and 6 to each other, the conic ends 21 of the pins 18 and the centering depressions 22 in the chocks 5 come into contact with each other, and thus form a stable support for the individual components of the roll set during the roll change.

The bores 19 and the centering depressions 22 in the chocks can be very simply manufactured. The pins 18 do not have to be manufactured in one piece with the chocks. They can be formed as turned pieces and then be inserted firmly into the chocks in a very simple manner. Their length depends on the desired height displacement between work rolls 3 and 4 of the roll set, during the roll change. Thus it is possible to utilize the same set of roll chocks 5 and 6 for the support and guidance of the rolls 3 and 4 even though they present a larger diameter difference.

in accordance with the provisions of the patent statutes, l have explained the principle and operation of my invention and have illustrated and described what I consider to represent the best embodiment thereof.

I claim: 1. In a rolling mill having a pair of opposed upper and lower rolls received in the housing of said mill,

bearing chock assemblies mounted on journals of each roll to form two cooperative sets of bearing chock assemblies,

a pair of stationarily mounted projecting pins carried by and extending from said lower bearing chock assemblies of each set towards the upper cooperative bearing chock assembly of the same set,

the outer ends of said pins being conically formed,

a pair of bores in each of said upper bearing chock assemblies arranged to receive a pair of said pins of the same set of chock assemblies and wherein said pins have lengths slightly less than the depths of said bores so that during rolling the pins do not interfere with the vertical movement of said rolls,

a pair of recesses in each of said upper bearing chock assemblies spaced from said pair of bores along the axes of said rolls an equal distance from and on the same side of and adjacent to said pair of bores of the same set of chock assemblies, each bore being engageable by each of said pins when one of said rolls is moved axially of the other roll, said recesses being conically formed to form self-centering depressions for said outer ends of said pins, whereby assemblies is carried by said bearing chock assemblies of said lower roll.

UNETED STATES PATENT OFFICE CERTIFICATE OF CQRRECTION Patent No. 3,736,785 Dated June 5'. 197% Inventor(s) Hans Friedrich Marten It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column Lt, lines 22 to 2h, "pair of bores of the same set of chock assemblies, each bore being engagable by each of" should read pair of bores of the same set of chock assemblies, each recess being; engageable by one of Signed and sealed this 19th day of March 197A.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. C. MARSHALL DANN I Attesting Officer Commissioner of Patents FORM PO-1OSO (10-69) USCOMM DC 5376 p5g w u.s. GOVERNMENT PRINTING OFFICE: I969 o-sie-au. 

1. In a rolling mill having a pair of opposed upper and lower rolls received in the housing of said mill, bearing chock assemblies mounted on journals of each roll to form two cooperative sets of bearing chock assemblies, a pair of stationarily mounted projecting pins carried by and extending from said lower bearing chock assemblies of each set towards the upper cooperative bearing chock assembly of the same set, the outer ends of said pins being conically formed, a pair of bores in each of said upper bearing chock assemblies arranged to receive a pair of said pins of the same set of chock assemblies and wherein said pins have lengths slightly less than the depths of said bores so that during rolling the pins do not interfere with the vertical movement of said rolls, a pair of recesses in each of said upper bearing chock assemblies spaced from said pair of bores along the axes of said rolls an equal distance from and on the same side of and adjacent to said pair of bores of the same set of chock assemblies, each bore being engageable by each of said pins when one of said rolls is moved axially of the other roll, said recesses being conically formed to form self-centering depressions for said outer ends of said pins, whereby the weight of said upper roll and its bearing chock assemblies is carried by said bearing chock assemblies of said lower roll. 